1. Field of the Invention
The present invention relates to a vertical shaft fuel tank cap with a charcoal canister.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
In the current market, most fuel tank caps contain a containing room or containing cavity filled by charcoal powder. When the inner pressure of the fuel tank is higher than the outer pressure, to achieve internal-external pressure balance, the fuel vapor in the fuel tank passes through and gets filtered by charcoal powder. Then, the filtered fuel vapor is discharged to the atmosphere to achieve the goals of emission control and less environment pollution. However, not all fuel vapor can be absorbed in this way. When the inner temperature is too high, or there is too much vibration within the fuel tank, some liquid fuel enters the containing cavity, soaks the charcoal powder for long time, and then undermines the filtering performance of the charcoal powder.